1. Field of the Invention
The present invention generally relates to security. More specifically, the present invention provides techniques and mechanisms for periodically refreshing keying material without possible session hijacking and without user intervention.
2. Description of Related Art
Various key exchange and authentication protocols such as Internet Key Exchange (IKE) allow entities to share information to generate a session key. IKE can be used to establish an Internet Protocol Security (IPsec) Virtual Private Network connection. IKE includes several phases. During IKE phase 1, two entities are generally authenticated and a matching IKE security association (SA) policy between the peers is negotiated to protect the IKE exchange. A key generation exchange such as a Diffie-Hellman exchange is performed to allow both entities to generate shared secret keys or session keys. During IKE phase 2, IPSec SA parameters protected by an existing IKE SA are negotiated. IPSec SAs are established and periodically renegotiated to ensure security. Optional additional Diffie-Hellman exchanges can also be performed.
To safeguard a connection against cryptographic attacks, the keying material needs to be periodically refreshed. Refreshing keying material typically entails prompting the user again for credential information in IKE. However, having to prompt the user again for credential information is annoying and problematic. The user may not be sitting in front of a terminal, or a user can be disconnected. To circumvent this situation, some vendors allow administrators to refresh keying material without prompting the user. However, this allows possible session hijacking attacks.
Current implementations for refreshing keying material associated with IKE SAs have limitations. Consequently, the techniques of the present invention provide mechanisms for allowing keying material to be periodically refreshed without possible session hijacking and without requiring user interaction.